PACKAGES

Overview

This chapter describes the architecture and some special design considerations and features for each of the ATCS packages.

For each package a standard documentation template has been used. This template includes:

• Short description and package name
• Inheritance information.
  Inheritance makes easier to group common functionality in a base class, described only once. In particular almost all packages follow standard conventions and implement a set of standard commands and a standard state machine. This is captured inheriting the packages from a Standard Package base class.
• A Use Case Diagram.
  This diagrams shows all Use Cases that are responsibility of the package, seen as a black box. A detailed description of each Use Case can be found in Appendix. During the preliminary design phase, Use Cases have been analyzed, refined and, when necessary, restructured, in order to assign every Use Case to one specific package. All other packages are, in this perspective, actors interacting with the package.
• A Class Diagram.
  This diagram describes the interactions of the package, represented by a black box class, with the other ATCS packages and with external systems. It represents the Level 0 context diagram of the package. The logical merge of all these diagrams represents all the interactions of the external systems with the ATCS and all internal interactions between packages. It constitutes then the Level 1 Context Diagram of the ATCS.
• Detailed architectural description.
• Reuse considerations.
  Since the ATCS strongly reuses the VLT TCS for the Unit Telescopes, a specific section provides some consideration on the extent of reuse possible for each package. The Code Reuse Analysis section provides some generic consideration on software reuse and a summary of the reuse of packages in the whole ATCS.

For a detailed description of the sections in the documentation template, see the help section in the ATCS online documentation.

More details on the architecture of the packages are given in the corresponding VLT UT TCS design documentation for that package or will be given in a specific design document for the ATCS package, if the deviation from the UT implementation will require writing a specific document.